CMTC-1 breast cancers were generally ER+, smaller tumor size, low grade and node negative; CMTC-2 breast cancers were ER+, but larger tumor size, higher grade and more nodal disease; and CMTC-3 breast cancers are more commonly found in younger patients, HER2+/TN, larger tumor size, and more nodal disease. The gene discussed is ESR1; the disease is breast cancer.